Automatic electric regulator.



F. E. RICKETTS. AUTQMATIIG ELECTRIC REGULATOR.

APPLICATION FILED JULY 23, 1910.

1,096,755. Patented May 12, 1914.

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Witnesses Inventor,

0%. Attorneys FORREST E. RICKETTS, OF BALTIMORE, MARYLAND.

AUTOMATIC ELECTRIC REGULATOR.

Specification of Letters Patent.

Patented May 12, 1914.

Application filed July 23, 1910. Serial No. 573,506.

T all whom it may concern:

Be it known that 1, Former E. RIGKE'lTS, a citizen of the l nitedStates, residing at the city of Baltimore, State of Maryland, haveinvented a new and useful Improvement for Automatic Electric Regulators,of which the following is a specification.

The present. invention relates to improvements in automatic electricregulators adapted for controlling the field current of electricgenerate-rs in response to'variations of electric conditions in thearmature circuit.

In accordance with the present invention the'field current of thegenerator is controlled by means of a regulating dynamo, the fieldcircuit of which is controlled by an automatic switch adapted foropening and closing a circuit of small current strength. The regulatingdynamo is here shown with its armature circuit in series with a batteryin which case its voltage is only a small part of the field voltage. Ifthe battery is omitted the voltage of the regulating dynamo will beequal to that of the field circuit of the generator in which case itwill perform the part of an exciter for the generator as well as that ofthe regulating generator.

Regulation is accomplished through a series of machines each of whichhas a certain amount of inductance which tends to delay the response tothe automatic switch. Therefore before the cttect of the automaticswitch could he felt on the circuit to be regulated to thereby cause theautomatic switch to reverse its action the first machine of the se-.ries will have built up a voltage so much in. excess of that requiredthat it will be slow in responding to the action. of the automaticswitch. That is, it will have to reduce its voltage to normal before itcan actively respond to the action of the automatic switch. This willresult in marked surges in the voltage of the circuit to be regulated.to

which surges the regulator will be slow to respond.

In the present invention the automatic switch is made responsive to thevoltage of each step of the series so that anyone of the machines canact to reverse the action of" the automatic switch independent of theothers. thereby keeping the voltage thictuations of the various stepswithin narrow limits.

To better understand the invention, reference will be made to theaccompanying drawing, forming a part of this specification, in which isillustrated an application of the controlling means in operatingrelation to an electric system to be regulated.

In the drawing there is shown a generator. l of the revolving fieldtype. i

The field current isfurnished by means of any suitable source ofelectricity which in the system illustrated is a battery 2. One side,Say the positive side, of the battery is connected to an exciter main 3while the other side is connected to another exciter main 4. The excitermain 3 is connected through the conductor 5 to one terminal of a dynamo6. The other terminal of the dynamo 6 is connected through conductor 7to a conductor 8. The field coils of the generator l are connectedthrough conductors 9 and 10 respectively, to the conductors 4 and 8.

The dynamo (S has a field coil 11 one terminal of which is connectedthrough a conductor 12 to the positive main 8, the other teri'ninal oi":the field coil 11 is connected through a conductor 13 to one terminal ofan e-Xciter 14. The other terminal of the cxciter ll is connectedthrough conductor 15 resistance 16, and conductor 17 to the negativemain 4. The field coil 18 of the exciter 14 is connected in parallelwith the resistance 91 through conductors 19 and 20, COIldUCl'OI. 19 isconnected through resistance 522 and conductor 23 to the positive mainThe conductor is connected through conductor ill to the negative main 4.An automatic switch adapted for shortcircuiting the field coil 18 iscomposed of two levers. one 25 is pivoted at the point 26 andelectrically connected to conductor 20 through a conductor 2?, the otherlever 28 is pivoted at the point 29 and connected by conductor 30 to theconductor 19. he lever 25 is under the control of the spring 31 tendingto open the contacts 33 and 34 and the magnet. 32 tending to close thecontacts 33 and 34. The lever 28 is under the con trol of a spring 35tending to open the contacts and 34; and the core 36 tending to closethe contacts 33 and 34-.

The core 32 is freely suspended in a solenoid 37 so related thereto asto eXertan upward pull on the core when an electric current is passedthrough the solenoid. One

tern'linal ot' the solenoid 37 is connected through a conductor 38 tothe positive main 8, the other terminal being connected throughconductor 39 resistance 40, and conductor 4:1 to conductor 15. The core36 is freely suspended in two solenoids 42 and 43. The solenoid 42 isconnected through conductor 44 and the conductor 45, resistance 46, andconductor 47, to a transformer 48 which is connected across the armatureleads 49 and 50 of the generator 1.

The solenoid 43 is connected through conductors 51 and 52 to a currenttransformer 53 whichis connected in series with one of the armatureleads of the generator 1. The solenoid 42 is so related to the core 36that an electric current passing through it will tend to pull down onthe core 36 and the solenoid 43 is so placed that a current passingthrough it will tend to oppose the pull of the solenoid 42. Let it beassumed that the lever 28 has been moved by the core 36 until thecontact 34 engages the contact 33. Then current will fiow from thepositive main 3 through the conductor 23, resistance 22 to the conductor19, then through conductor 30, levers 28 and 25 and conductor 27 toconductor 20 then through conductor 24 to the negative main 4. Owing tothe low resistance of the path from conductor 19 to conductor 20 by wayof the levers 28 and 25, no current will flow through the field coil 18.This will (.llOW the difference of potential between the armatureterminals of the eXciter 14 to drop to zero. Then current will flow fromthe positive main 8 through conductor 12, field coil 1.1, conductor 13,armature of exciter 14, conductor 15, resistance 16 and conductor 1.7 tothe negative main 4. This current passing through the field coil 11 willcause the dynamo 6 to; generate a potential between conductors 5 and 7in a direction to lower the potential of the armature leads 49 and 50.This will be called a negative voltage being in a direction to lower thevoltage to be regulated 'When however the contacts 33 and 34 separatethe current flowing through conductor 23 and resistance 22 will divideat the conductor 19 part flowing through resistance 21 and part throughfield coil 18 combining again at conductor 20 and re turning to main 4by way of conductor 24. The resistance 21 may be omitted which wouldcause all the current flowing in resistance 22 to flow through the fieldcoil. 18 but owing to the inductance of the field coil 1-8 this wouldcause a high voltage between contacts 33 and 34, at the instant thecontact was broken. lf the resistance 21 were omitted, when the contacts33 and 34 are together all of the current flowing through resistance 22would pass through the contacts. but the instant contact was broken theinductance of the field coil 18 would oppose the sudden building up ofthe current in. the coil, which would. be nearly equivalent to openingthe circuit with the contacts and the instantaneous voltage across thecontacts would approximate the voltage of the conductors 3 and 4. Inpractice this would destroy the contacts. This current flowing throughthe field coil 18 will cause the exciter 14 to generate a potential inthe direction to oppose the flow of current from the main 8 through thefield coil 11 and if the contacts 33 and 34 remain open long enough thevoltage of the exciter 14 will buildup sufficiently to not only decreasethe flow of current from main 8 through field coil 11, but also to causecurrent to flow from main 4 through field coil 11 to main 8 therebyreversing the polarity of the dynamo 6. This latter polarity of thedynamo 6 Will be in the direction to increase the voltage of theenerator 1 and therefore will be referred to s a positive voltage. Itwill be understood that owing to the inductance of the circuits of theexciter 14 and dynamo 6 the contacts 33 and 34 can be opened and closedfast enough to prevent the voltages of the machines 14 and 6 frombuilding up to the maximum allowing the voltage of the dynamo 6 toremain reasonably constant at any point between the maximum positive andthe maximum negative.

Means for actuating the contacts so as to accomplish this result isshown in the drawing as a core 32 actuated by a solenoid 37 which isinfluenced by the voltages of the machines 14 and 6. The automaticswitch is also made responsive to the voltage of the armature circuit ofthe generator 1 by means of a core 36 which is under the control of thecoil 42 which is under the influence of the voltage of the transformer48 which is so constructed as to supply to the coil 42 a voltage alwaysb aring a certain ratio to the voltage of the armature circuit ofgenerator 1. The coil 43 on the magnet 36 is energized by currentinductively generated in the secondary of the transformer 53 and isproportional to the current in the main 50. Therefore the pull exertedon the core 36 is the resultant of the pulls due to the current andvoltage elements of the armature leads of the generator 1. The result ofthis will be to cause the lever 28 to operate to increase the voltage ofthe armature leads of the generator 1 as the cur-' rent in the armaturecircuit increases. The switch lever 25 1s under-the influence of thesolenoid 37 which is connected between the main 8 and conductor 15 andin series with the resistance 40 which is used to protect the coil 37and to cause the core 32 to respond quickly to changes in voltagebetween main 8 and conductor 15. That is it gives to the circuit whichcontains the coil. 37 a high ohmic component theroliv reducing the timeconstant, of the circdi l. The reason for connecting conductor 41 oconductor 15 instead of directly to the main 4 may be described asfollows: A certain emount of current will flow from the main I pend 8through conductor 38, coil 37, conductor 39, resistance 40, conductor41, to conductor 15 then through resistance 16 and conductor 17 to main4. Since the resistance of the conductors 17, 15, 41, 39 and 38 arenegligible the voltage drop along this circuit will be divided intothree parts that of the resistances 16 the resistance 40 and the coil37. The voltage drop across each of these elements will depend upon thecurrent flowing in that element.

It Will be seen that not only the current passing from main 8 throughthe coil 37 and resistance 40 but also the current passing from main 8through field coil 11 and machine 14 will pass through the resistance16. The amount of this current flowing by way of coil 37 and resistance40 will deupon the voltage of the field mains 8 and 4 and the amount ofcurrent flowing by Way of field coil 11 and armature 14 will depend uponthe algebraic sum of the' voltages of the field mains 8 and 4 and thatof the armature 14. Therefore the lever will be responsive to thevoltage of the field mains 8 and 4 and also to that of the machine 14.And since the lever 28 is responsive to variation in the voltage of thearmature leads 49 and 50 the automatic switch composed of the levers 25and 28 will be responsive to variations of voltage of either of themachines 1, 6 or 14. This is an important feature of my invention.

Vhen the apparatus herein described has .been properly connected andadjusted it will operate in the following manner to maintain a constantvoltage on the armature leads 49 and 50, or if it is so desired the coil43 can be adjusted so that thevoltage on the mains 49 and 50 willincrease as the cm rent flowing in the main 50 increases. We will assumefor example that the voltage on the mains 49 and 50 has decreasedsutficiently to alldw the spring to pull the contact 34 away from thecontact Then the current which has been flowing through the contacts 33and 34 will have to divide through the field coil 18 and the resistance21. The direction of this current through the field 18 Will be such asto cause the machine 14 to generate a voltage opposing the flow ofcurrent frommain 8 through the field coil 11 machine 14 and resistance16 back to main 4. The instant this cur rent decreases the potentialdrop across the resistance 16 will decrease and since the algebraic sumof the voltages across resistance-s 16 and and coil. 37 always equalsthe voltage across the mains 4- and 8 the voltage across the resistance40 and coil 37 will increase and cause tho'coil 37 to exerta greaterpull on the core 32 tending to overcome the spring 31 to bring thecontact 33 against the contact 34.

The decreaSe of current in the circuit containing field coil 11 machine14, and resistance 16 aside from decreasing the potential drop acrossthe resistance 16 Will vary the voltage of machine 6 in the direction toraise the voltage of mains 4 and 8 which will increase the voltageacross the resistance 16 and 40 and the coil 37. This increase ofvoltage across the coil 37 will tend to raise the core 32 to close thecontacts 33 and 34. The increase of voltage on the mains 4 and 8 willalso cause more current to flow through the field coils of the generator1 to increase the voltage of the mains 49 and 50. This increase ofvoltage on the mains 49 and will increase the pull of the coil 42 on thecore 56 to bring the contact 34 against the contact 33. \Vhen the sum ofthese three pulls is suflicient to overcome the springs 31 and 35 andbring the contacts and 34 into contact the field coil 18 will beshort-circuited and the voltage of the machine 14 will. begin todecrease allowing the current flowing from main 8 through field coil 11machine 14 and resistance 16 to increase thereby increasing the voltagedrop across the resistance 16 which will. decrease the voltage acrossresistance 40 andcoil 37 since the algebraic sum of these three voltagesequals the voltage across the mains 4 and 8. This decrease of voltageacross the coil 87 will tend ,to open the contacts 33 and This increaseof current flowing from main 8 through field coil 11 will vary thevoltage of the machine 6 to decrease the voltage of the mains 4 and 8which will also tend to weaken the pull of the coil 37 on the corethereby assisting the spring 31. to open the contacts 33 an 34 but thedecrease of voltage on the mains 4 and 8 will cause less current to flowthrough the field of generator 1 thereby decreasing the voltage of themains 49 and 50, which will weaken the coil 42 and allow the spring topull contact 33-away from contact 34 which will cause current to againflow through the field l8 whereupon the apparatus will start on a secondcycle of operation similar to the one just described. When the apparatusis once in operation it will continue to ass through these cycles ofoperation, regart less of the condition of the circuit to be regulated.The relative duration of the different parts of the cycle however isdependent upon the condition of the circuit to be. regulated. Erom thisit will be seen that the automatic switch composed of the lovers 25 and28 is responsive to each of the voltages of the-system independent ofthe others'and therefore will operate to prevent any marked variationsin either of said voltages. lVhen the current in the armature circuit ofthe generator increases the current supplied to the coil 43 by thetransformer 53 will increase and partly neutralize the effect of coil 42on core 36 and a greater voltage will be required on the mains 49 and toovercome the spring 35 and the regulator will operate to increase thevoltage of the system as the current flowing in the armature circuit ofthe generator 1 increases. The dynamo 6 will be of sufficient capacityto furnish the exciter, current for the generator 1 and the excit-er 14will be of sufficient capacity to furnish the field current for dynamo6. The resistance 16 will have about one ohm resistance and be ofsuflicient carrying capacity to carry the field current of dynamo 6. Theresistances 21 and 22 wil.- be of sufiicient carrying capacity and havesufficient resistance that when the contacts 33 and 34: are open thevoltage of the exciter 14 will equal twice the voltage of the mains 4and 8.

What is claimed is: y

1. The combination of an alternating current generator, a circuit ofconstant polarity, a dynamo having its armature circuit in series with,and its field circuit in parallel with the field circuit of saidgenerator, an exciter having its armature circuit in series with thefield of said dynamo and its field circuit connected to said circuit ofconstant polarity and means controlled by the voltage of the generator,by the voltage of the dynamo and by the voltage of the eXciter' forcontrolling the voltage of the exciter.

2. The combination of an alternating current generator, a dynamo havingits armature circuit in series with the field of said generator, meansfor supplying to the field of the dynamo a voltage of constant polarity,a source of electromotive-force for opposing said voltage of constantpolarity, a pair of contacts for controlling 'the voltage of saidsource, and means for'actuating the contacts to cause the voltage of thedynamo to vary through zero.

3. The combination of an alternating current generator, a dynamo havingits armature circuit in series with the field of said generator, meansfor supplying to the field of said dynamo a voltage of constantpolarity, voltage producing means for opposing said voltage of constantpolarity, and means controlled by the voltage of said generator forcontrolling the voltage of said voltage producing means to cause thedynamo to work first at one polarity and then at the other.

4. In an electric system a generator having an armature circuit and afield circuit, a dynamo having its armature circuit in series with thefield circuit of the generator and its field circuit in paralleltherewith, an exciter having its armature circuit in series with thefield circuit of the dynamo and its field circuit in parallel therewithand means responsive to changes of electrical condition in the armaturecircuit of the generator for controlling the voltage of the exciter.

5. In an electric system a generator having an armature circuit and afield circuit, a dynamo having its armature circuit in series with thefield circuit of the generator and its field circuit in paralleltherewith, an exciter having its armature circuit in series with thefield circuit of the dynamo and its field circuit in parallel therewithand means responsive to changes of electrical condition in the armaturecircuit of the exciter for controlling the voltage of the exciter.

6. In an electric system a generator having an armature circuit and afield circuit, a dynamo having its armature circuit in series with thefield circuit of the generator.

and its field circuit in parallel therewith, an exciter having itsarmature circuit in series with the field circuit of'the dynamo and itsfield circuit in parallel therewith and means responsive to changes ofelectrical condition in the armature circuits of the generatonthevdynamo and the exciter for controlling the voltage of the exciter.

In testimony that I claim the foregoing as my own, I have hereto afiixedmy signature in the presence of two witnesses.

FORREST E. RICKETTS. Witnesses:

Join: T. FARDY, STEPHEN D. BROADTENT,

